2 * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
3 * Copyright (C) 2013 - Raphaël Beamonte <raphael.beamonte@gmail.com>
4 * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License, version 2 only, as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
27 #include <sys/types.h>
35 #include <common/common.h>
36 #include <common/readwrite.h>
37 #include <common/runas.h>
38 #include <common/compat/getenv.h>
39 #include <common/compat/string.h>
40 #include <common/compat/dirent.h>
41 #include <lttng/constant.h>
47 #define PROC_MEMINFO_PATH "/proc/meminfo"
48 #define PROC_MEMINFO_MEMAVAILABLE_LINE "MemAvailable:"
49 #define PROC_MEMINFO_MEMTOTAL_LINE "MemTotal:"
51 /* The length of the longest field of `/proc/meminfo`. */
52 #define PROC_MEMINFO_FIELD_MAX_NAME_LEN 20
54 #if (PROC_MEMINFO_FIELD_MAX_NAME_LEN == 20)
55 #define MAX_NAME_LEN_SCANF_IS_A_BROKEN_API "19"
57 #error MAX_NAME_LEN_SCANF_IS_A_BROKEN_API must be updated to match (PROC_MEMINFO_FIELD_MAX_NAME_LEN - 1)
61 * Return a partial realpath(3) of the path even if the full path does not
62 * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist
63 * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with
64 * /test2/test3 then returned. In normal time, realpath(3) fails if the end
65 * point directory does not exist.
66 * In case resolved_path is NULL, the string returned was allocated in the
67 * function and thus need to be freed by the caller. The size argument allows
68 * to specify the size of the resolved_path argument if given, or the size to
72 char *utils_partial_realpath(const char *path
, char *resolved_path
, size_t size
)
74 char *cut_path
= NULL
, *try_path
= NULL
, *try_path_prev
= NULL
;
75 const char *next
, *prev
, *end
;
83 * Identify the end of the path, we don't want to treat the
84 * last char if it is a '/', we will just keep it on the side
85 * to be added at the end, and return a value coherent with
86 * the path given as argument
88 end
= path
+ strlen(path
);
89 if (*(end
-1) == '/') {
93 /* Initiate the values of the pointers before looping */
96 /* Only to ensure try_path is not NULL to enter the while */
97 try_path
= (char *)next
;
99 /* Resolve the canonical path of the first part of the path */
100 while (try_path
!= NULL
&& next
!= end
) {
101 char *try_path_buf
= NULL
;
104 * If there is not any '/' left, we want to try with
107 next
= strpbrk(next
+ 1, "/");
112 /* Cut the part we will be trying to resolve */
113 cut_path
= lttng_strndup(path
, next
- path
);
114 if (cut_path
== NULL
) {
115 PERROR("lttng_strndup");
119 try_path_buf
= zmalloc(LTTNG_PATH_MAX
);
125 /* Try to resolve this part */
126 try_path
= realpath((char *) cut_path
, try_path_buf
);
127 if (try_path
== NULL
) {
130 * There was an error, we just want to be assured it
131 * is linked to an unexistent directory, if it's another
132 * reason, we spawn an error
136 /* Ignore the error */
139 PERROR("realpath (partial_realpath)");
144 /* Save the place we are before trying the next step */
147 try_path_prev
= try_path
;
151 /* Free the allocated memory */
156 /* Allocate memory for the resolved path if necessary */
157 if (resolved_path
== NULL
) {
158 resolved_path
= zmalloc(size
);
159 if (resolved_path
== NULL
) {
160 PERROR("zmalloc resolved path");
166 * If we were able to solve at least partially the path, we can concatenate
167 * what worked and what didn't work
169 if (try_path_prev
!= NULL
) {
170 /* If we risk to concatenate two '/', we remove one of them */
171 if (try_path_prev
[strlen(try_path_prev
) - 1] == '/' && prev
[0] == '/') {
172 try_path_prev
[strlen(try_path_prev
) - 1] = '\0';
176 * Duplicate the memory used by prev in case resolved_path and
177 * path are pointers for the same memory space
179 cut_path
= strdup(prev
);
180 if (cut_path
== NULL
) {
185 /* Concatenate the strings */
186 snprintf(resolved_path
, size
, "%s%s", try_path_prev
, cut_path
);
188 /* Free the allocated memory */
192 try_path_prev
= NULL
;
194 * Else, we just copy the path in our resolved_path to
198 strncpy(resolved_path
, path
, size
);
201 /* Then we return the 'partially' resolved path */
202 return resolved_path
;
208 if (try_path_prev
!= try_path
) {
215 int expand_double_slashes_dot_and_dotdot(char *path
)
217 size_t expanded_path_len
, path_len
;
218 const char *curr_char
, *path_last_char
, *next_slash
, *prev_slash
;
220 path_len
= strlen(path
);
221 path_last_char
= &path
[path_len
];
227 expanded_path_len
= 0;
229 /* We iterate over the provided path to expand the "//", "../" and "./" */
230 for (curr_char
= path
; curr_char
<= path_last_char
; curr_char
= next_slash
+ 1) {
231 /* Find the next forward slash. */
232 size_t curr_token_len
;
234 if (curr_char
== path_last_char
) {
239 next_slash
= memchr(curr_char
, '/', path_last_char
- curr_char
);
240 if (next_slash
== NULL
) {
241 /* Reached the end of the provided path. */
242 next_slash
= path_last_char
;
245 /* Compute how long is the previous token. */
246 curr_token_len
= next_slash
- curr_char
;
247 switch(curr_token_len
) {
250 * The pointer has not move meaning that curr_char is
251 * pointing to a slash. It that case there is no token
252 * to copy, so continue the iteration to find the next
258 * The pointer moved 1 character. Check if that
259 * character is a dot ('.'), if it is: omit it, else
260 * copy the token to the normalized path.
262 if (curr_char
[0] == '.') {
268 * The pointer moved 2 characters. Check if these
269 * characters are double dots ('..'). If that is the
270 * case, we need to remove the last token of the
273 if (curr_char
[0] == '.' && curr_char
[1] == '.') {
275 * Find the previous path component by
276 * using the memrchr function to find the
277 * previous forward slash and substract that
278 * len to the resulting path.
280 prev_slash
= lttng_memrchr(path
, '/', expanded_path_len
);
282 * If prev_slash is NULL, we reached the
283 * beginning of the path. We can't go back any
286 if (prev_slash
!= NULL
) {
287 expanded_path_len
= prev_slash
- path
;
297 * Copy the current token which is neither a '.' nor a '..'.
299 path
[expanded_path_len
++] = '/';
300 memcpy(&path
[expanded_path_len
], curr_char
, curr_token_len
);
301 expanded_path_len
+= curr_token_len
;
304 if (expanded_path_len
== 0) {
305 path
[expanded_path_len
++] = '/';
308 path
[expanded_path_len
] = '\0';
315 * Make a full resolution of the given path even if it doesn't exist.
316 * This function uses the utils_partial_realpath function to resolve
317 * symlinks and relatives paths at the start of the string, and
318 * implements functionnalities to resolve the './' and '../' strings
319 * in the middle of a path. This function is only necessary because
320 * realpath(3) does not accept to resolve unexistent paths.
321 * The returned string was allocated in the function, it is thus of
322 * the responsibility of the caller to free this memory.
325 char *_utils_expand_path(const char *path
, bool keep_symlink
)
328 char *absolute_path
= NULL
;
330 bool is_dot
, is_dotdot
;
337 /* Allocate memory for the absolute_path */
338 absolute_path
= zmalloc(LTTNG_PATH_MAX
);
339 if (absolute_path
== NULL
) {
340 PERROR("zmalloc expand path");
344 if (path
[0] == '/') {
345 ret
= lttng_strncpy(absolute_path
, path
, LTTNG_PATH_MAX
);
347 ERR("Path exceeds maximal size of %i bytes", LTTNG_PATH_MAX
);
352 * This is a relative path. We need to get the present working
353 * directory and start the path walk from there.
355 char current_working_dir
[LTTNG_PATH_MAX
];
358 cwd_ret
= getcwd(current_working_dir
, sizeof(current_working_dir
));
363 * Get the number of character in the CWD and allocate an array
364 * to can hold it and the path provided by the caller.
366 ret
= snprintf(absolute_path
, LTTNG_PATH_MAX
, "%s/%s",
367 current_working_dir
, path
);
368 if (ret
>= LTTNG_PATH_MAX
) {
369 ERR("Concatenating current working directory %s and path %s exceeds maximal size of %i bytes",
370 current_working_dir
, path
, LTTNG_PATH_MAX
);
376 /* Resolve partially our path */
377 absolute_path
= utils_partial_realpath(absolute_path
,
378 absolute_path
, LTTNG_PATH_MAX
);
381 ret
= expand_double_slashes_dot_and_dotdot(absolute_path
);
386 /* Identify the last token */
387 last_token
= strrchr(absolute_path
, '/');
389 /* Verify that this token is not a relative path */
390 is_dotdot
= (strcmp(last_token
, "/..") == 0);
391 is_dot
= (strcmp(last_token
, "/.") == 0);
393 /* If it is, take action */
394 if (is_dot
|| is_dotdot
) {
395 /* For both, remove this token */
398 /* If it was a reference to parent directory, go back one more time */
400 last_token
= strrchr(absolute_path
, '/');
402 /* If there was only one level left, we keep the first '/' */
403 if (last_token
== absolute_path
) {
411 return absolute_path
;
418 char *utils_expand_path(const char *path
)
420 return _utils_expand_path(path
, true);
424 char *utils_expand_path_keep_symlink(const char *path
)
426 return _utils_expand_path(path
, false);
429 * Create a pipe in dst.
432 int utils_create_pipe(int *dst
)
442 PERROR("create pipe");
449 * Create pipe and set CLOEXEC flag to both fd.
451 * Make sure the pipe opened by this function are closed at some point. Use
452 * utils_close_pipe().
455 int utils_create_pipe_cloexec(int *dst
)
463 ret
= utils_create_pipe(dst
);
468 for (i
= 0; i
< 2; i
++) {
469 ret
= fcntl(dst
[i
], F_SETFD
, FD_CLOEXEC
);
471 PERROR("fcntl pipe cloexec");
481 * Create pipe and set fd flags to FD_CLOEXEC and O_NONBLOCK.
483 * Make sure the pipe opened by this function are closed at some point. Use
484 * utils_close_pipe(). Using pipe() and fcntl rather than pipe2() to
485 * support OSes other than Linux 2.6.23+.
488 int utils_create_pipe_cloexec_nonblock(int *dst
)
496 ret
= utils_create_pipe(dst
);
501 for (i
= 0; i
< 2; i
++) {
502 ret
= fcntl(dst
[i
], F_SETFD
, FD_CLOEXEC
);
504 PERROR("fcntl pipe cloexec");
508 * Note: we override any flag that could have been
509 * previously set on the fd.
511 ret
= fcntl(dst
[i
], F_SETFL
, O_NONBLOCK
);
513 PERROR("fcntl pipe nonblock");
523 * Close both read and write side of the pipe.
526 void utils_close_pipe(int *src
)
534 for (i
= 0; i
< 2; i
++) {
542 PERROR("close pipe");
548 * Create a new string using two strings range.
551 char *utils_strdupdelim(const char *begin
, const char *end
)
555 str
= zmalloc(end
- begin
+ 1);
557 PERROR("zmalloc strdupdelim");
561 memcpy(str
, begin
, end
- begin
);
562 str
[end
- begin
] = '\0';
569 * Set CLOEXEC flag to the give file descriptor.
572 int utils_set_fd_cloexec(int fd
)
581 ret
= fcntl(fd
, F_SETFD
, FD_CLOEXEC
);
583 PERROR("fcntl cloexec");
592 * Create pid file to the given path and filename.
595 int utils_create_pid_file(pid_t pid
, const char *filepath
)
602 fp
= fopen(filepath
, "w");
604 PERROR("open pid file %s", filepath
);
609 ret
= fprintf(fp
, "%d\n", (int) pid
);
611 PERROR("fprintf pid file");
618 DBG("Pid %d written in file %s", (int) pid
, filepath
);
625 * Create lock file to the given path and filename.
626 * Returns the associated file descriptor, -1 on error.
629 int utils_create_lock_file(const char *filepath
)
637 memset(&lock
, 0, sizeof(lock
));
638 fd
= open(filepath
, O_CREAT
| O_WRONLY
, S_IRUSR
| S_IWUSR
|
641 PERROR("open lock file %s", filepath
);
647 * Attempt to lock the file. If this fails, there is
648 * already a process using the same lock file running
649 * and we should exit.
651 lock
.l_whence
= SEEK_SET
;
652 lock
.l_type
= F_WRLCK
;
654 ret
= fcntl(fd
, F_SETLK
, &lock
);
656 PERROR("fcntl lock file");
657 ERR("Could not get lock file %s, another instance is running.",
660 PERROR("close lock file");
671 * On some filesystems (e.g. nfs), mkdir will validate access rights before
672 * checking for the existence of the path element. This means that on a setup
673 * where "/home/" is a mounted NFS share, and running as an unpriviledged user,
674 * recursively creating a path of the form "/home/my_user/trace/" will fail with
675 * EACCES on mkdir("/home", ...).
677 * Performing a stat(...) on the path to check for existence allows us to
678 * work around this behaviour.
681 int mkdir_check_exists(const char *path
, mode_t mode
)
686 ret
= stat(path
, &st
);
688 if (S_ISDIR(st
.st_mode
)) {
689 /* Directory exists, skip. */
692 /* Exists, but is not a directory. */
700 * Let mkdir handle other errors as the caller expects mkdir
703 ret
= mkdir(path
, mode
);
709 * Create directory using the given path and mode.
711 * On success, return 0 else a negative error code.
714 int utils_mkdir(const char *path
, mode_t mode
, int uid
, int gid
)
718 if (uid
< 0 || gid
< 0) {
719 ret
= mkdir_check_exists(path
, mode
);
721 ret
= run_as_mkdir(path
, mode
, uid
, gid
);
724 if (errno
!= EEXIST
) {
725 PERROR("mkdir %s, uid %d, gid %d", path
? path
: "NULL",
736 * Internal version of mkdir_recursive. Runs as the current user.
737 * Don't call directly; use utils_mkdir_recursive().
739 * This function is ominously marked as "unsafe" since it should only
740 * be called by a caller that has transitioned to the uid and gid under which
741 * the directory creation should occur.
744 int _utils_mkdir_recursive_unsafe(const char *path
, mode_t mode
)
746 char *p
, tmp
[PATH_MAX
];
752 ret
= snprintf(tmp
, sizeof(tmp
), "%s", path
);
754 PERROR("snprintf mkdir");
759 if (tmp
[len
- 1] == '/') {
763 for (p
= tmp
+ 1; *p
; p
++) {
766 if (tmp
[strlen(tmp
) - 1] == '.' &&
767 tmp
[strlen(tmp
) - 2] == '.' &&
768 tmp
[strlen(tmp
) - 3] == '/') {
769 ERR("Using '/../' is not permitted in the trace path (%s)",
774 ret
= mkdir_check_exists(tmp
, mode
);
776 if (errno
!= EACCES
) {
777 PERROR("mkdir recursive");
786 ret
= mkdir_check_exists(tmp
, mode
);
788 PERROR("mkdir recursive last element");
797 * Recursively create directory using the given path and mode, under the
798 * provided uid and gid.
800 * On success, return 0 else a negative error code.
803 int utils_mkdir_recursive(const char *path
, mode_t mode
, int uid
, int gid
)
807 if (uid
< 0 || gid
< 0) {
808 /* Run as current user. */
809 ret
= _utils_mkdir_recursive_unsafe(path
, mode
);
811 ret
= run_as_mkdir_recursive(path
, mode
, uid
, gid
);
814 PERROR("mkdir %s, uid %d, gid %d", path
? path
: "NULL",
822 * path is the output parameter. It needs to be PATH_MAX len.
824 * Return 0 on success or else a negative value.
826 static int utils_stream_file_name(char *path
,
827 const char *path_name
, const char *file_name
,
828 uint64_t size
, uint64_t count
,
832 char full_path
[PATH_MAX
];
833 char *path_name_suffix
= NULL
;
836 ret
= snprintf(full_path
, sizeof(full_path
), "%s/%s",
837 path_name
, file_name
);
839 PERROR("snprintf create output file");
843 /* Setup extra string if suffix or/and a count is needed. */
844 if (size
> 0 && suffix
) {
845 ret
= asprintf(&extra
, "_%" PRIu64
"%s", count
, suffix
);
846 } else if (size
> 0) {
847 ret
= asprintf(&extra
, "_%" PRIu64
, count
);
849 ret
= asprintf(&extra
, "%s", suffix
);
852 PERROR("Allocating extra string to name");
857 * If we split the trace in multiple files, we have to add the count at
858 * the end of the tracefile name.
861 ret
= asprintf(&path_name_suffix
, "%s%s", full_path
, extra
);
863 PERROR("Allocating path name with extra string");
864 goto error_free_suffix
;
866 strncpy(path
, path_name_suffix
, PATH_MAX
- 1);
867 path
[PATH_MAX
- 1] = '\0';
869 ret
= lttng_strncpy(path
, full_path
, PATH_MAX
);
871 ERR("Failed to copy stream file name");
872 goto error_free_suffix
;
875 path
[PATH_MAX
- 1] = '\0';
878 free(path_name_suffix
);
886 * Create the stream file on disk.
888 * Return 0 on success or else a negative value.
891 int utils_create_stream_file(const char *path_name
, char *file_name
, uint64_t size
,
892 uint64_t count
, int uid
, int gid
, char *suffix
)
894 int ret
, flags
, mode
;
897 ret
= utils_stream_file_name(path
, path_name
, file_name
,
898 size
, count
, suffix
);
904 * With the session rotation feature on the relay, we might need to seek
905 * and truncate a tracefile, so we need read and write access.
907 flags
= O_RDWR
| O_CREAT
| O_TRUNC
;
908 /* Open with 660 mode */
909 mode
= S_IRUSR
| S_IWUSR
| S_IRGRP
| S_IWGRP
;
911 if (uid
< 0 || gid
< 0) {
912 ret
= open(path
, flags
, mode
);
914 ret
= run_as_open(path
, flags
, mode
, uid
, gid
);
917 PERROR("open stream path %s", path
);
924 * Unlink the stream tracefile from disk.
926 * Return 0 on success or else a negative value.
929 int utils_unlink_stream_file(const char *path_name
, char *file_name
, uint64_t size
,
930 uint64_t count
, int uid
, int gid
, char *suffix
)
935 ret
= utils_stream_file_name(path
, path_name
, file_name
,
936 size
, count
, suffix
);
940 if (uid
< 0 || gid
< 0) {
943 ret
= run_as_unlink(path
, uid
, gid
);
949 DBG("utils_unlink_stream_file %s returns %d", path
, ret
);
954 * Change the output tracefile according to the given size and count The
955 * new_count pointer is set during this operation.
957 * From the consumer, the stream lock MUST be held before calling this function
958 * because we are modifying the stream status.
960 * Return 0 on success or else a negative value.
963 int utils_rotate_stream_file(char *path_name
, char *file_name
, uint64_t size
,
964 uint64_t count
, int uid
, int gid
, int out_fd
, uint64_t *new_count
,
973 PERROR("Closing tracefile");
980 * In tracefile rotation, for the relay daemon we need
981 * to unlink the old file if present, because it may
982 * still be open in reading by the live thread, and we
983 * need to ensure that we do not overwrite the content
984 * between get_index and get_packet. Since we have no
985 * way to verify integrity of the data content compared
986 * to the associated index, we need to ensure the reader
987 * has exclusive access to the file content, and that
988 * the open of the data file is performed in get_index.
989 * Unlinking the old file rather than overwriting it
993 *new_count
= (*new_count
+ 1) % count
;
995 ret
= utils_unlink_stream_file(path_name
, file_name
, size
,
996 new_count
? *new_count
: 0, uid
, gid
, 0);
997 if (ret
< 0 && errno
!= ENOENT
) {
1006 ret
= utils_create_stream_file(path_name
, file_name
, size
,
1007 new_count
? *new_count
: 0, uid
, gid
, 0);
1022 * Parse a string that represents a size in human readable format. It
1023 * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
1025 * The suffix multiply the integer by:
1030 * @param str The string to parse.
1031 * @param size Pointer to a uint64_t that will be filled with the
1034 * @return 0 on success, -1 on failure.
1037 int utils_parse_size_suffix(const char * const str
, uint64_t * const size
)
1042 const char *str_end
;
1046 DBG("utils_parse_size_suffix: received a NULL string.");
1051 /* strtoull will accept a negative number, but we don't want to. */
1052 if (strchr(str
, '-') != NULL
) {
1053 DBG("utils_parse_size_suffix: invalid size string, should not contain '-'.");
1058 /* str_end will point to the \0 */
1059 str_end
= str
+ strlen(str
);
1061 base_size
= strtoull(str
, &num_end
, 0);
1063 PERROR("utils_parse_size_suffix strtoull");
1068 if (num_end
== str
) {
1069 /* strtoull parsed nothing, not good. */
1070 DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
1075 /* Check if a prefix is present. */
1093 DBG("utils_parse_size_suffix: invalid suffix.");
1098 /* Check for garbage after the valid input. */
1099 if (num_end
!= str_end
) {
1100 DBG("utils_parse_size_suffix: Garbage after size string.");
1105 *size
= base_size
<< shift
;
1107 /* Check for overflow */
1108 if ((*size
>> shift
) != base_size
) {
1109 DBG("utils_parse_size_suffix: oops, overflow detected.");
1120 * Parse a string that represents a time in human readable format. It
1121 * supports decimal integers suffixed by:
1122 * "us" for microsecond,
1123 * "ms" for millisecond,
1128 * The suffix multiply the integer by:
1135 * Note that unit-less numbers are assumed to be microseconds.
1137 * @param str The string to parse, assumed to be NULL-terminated.
1138 * @param time_us Pointer to a uint64_t that will be filled with the
1139 * resulting time in microseconds.
1141 * @return 0 on success, -1 on failure.
1144 int utils_parse_time_suffix(char const * const str
, uint64_t * const time_us
)
1148 uint64_t multiplier
= 1;
1149 const char *str_end
;
1153 DBG("utils_parse_time_suffix: received a NULL string.");
1158 /* strtoull will accept a negative number, but we don't want to. */
1159 if (strchr(str
, '-') != NULL
) {
1160 DBG("utils_parse_time_suffix: invalid time string, should not contain '-'.");
1165 /* str_end will point to the \0 */
1166 str_end
= str
+ strlen(str
);
1168 base_time
= strtoull(str
, &num_end
, 10);
1170 PERROR("utils_parse_time_suffix strtoull on string \"%s\"", str
);
1175 if (num_end
== str
) {
1176 /* strtoull parsed nothing, not good. */
1177 DBG("utils_parse_time_suffix: strtoull had nothing good to parse.");
1182 /* Check if a prefix is present. */
1188 * Skip the "us" if the string matches the "us" suffix,
1189 * otherwise let the check for the end of the string handle
1190 * the error reporting.
1192 if (*(num_end
+ 1) == 's') {
1197 if (*(num_end
+ 1) == 's') {
1198 /* Millisecond (ms) */
1199 multiplier
= USEC_PER_MSEC
;
1204 multiplier
= USEC_PER_MINUTE
;
1210 multiplier
= USEC_PER_SEC
;
1215 multiplier
= USEC_PER_HOURS
;
1221 DBG("utils_parse_time_suffix: invalid suffix.");
1226 /* Check for garbage after the valid input. */
1227 if (num_end
!= str_end
) {
1228 DBG("utils_parse_time_suffix: Garbage after time string.");
1233 *time_us
= base_time
* multiplier
;
1235 /* Check for overflow */
1236 if ((*time_us
/ multiplier
) != base_time
) {
1237 DBG("utils_parse_time_suffix: oops, overflow detected.");
1248 * fls: returns the position of the most significant bit.
1249 * Returns 0 if no bit is set, else returns the position of the most
1250 * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
1252 #if defined(__i386) || defined(__x86_64)
1253 static inline unsigned int fls_u32(uint32_t x
)
1257 asm("bsrl %1,%0\n\t"
1261 : "=r" (r
) : "rm" (x
));
1267 #if defined(__x86_64)
1269 unsigned int fls_u64(uint64_t x
)
1273 asm("bsrq %1,%0\n\t"
1277 : "=r" (r
) : "rm" (x
));
1284 static __attribute__((unused
))
1285 unsigned int fls_u64(uint64_t x
)
1287 unsigned int r
= 64;
1292 if (!(x
& 0xFFFFFFFF00000000ULL
)) {
1296 if (!(x
& 0xFFFF000000000000ULL
)) {
1300 if (!(x
& 0xFF00000000000000ULL
)) {
1304 if (!(x
& 0xF000000000000000ULL
)) {
1308 if (!(x
& 0xC000000000000000ULL
)) {
1312 if (!(x
& 0x8000000000000000ULL
)) {
1321 static __attribute__((unused
)) unsigned int fls_u32(uint32_t x
)
1323 unsigned int r
= 32;
1328 if (!(x
& 0xFFFF0000U
)) {
1332 if (!(x
& 0xFF000000U
)) {
1336 if (!(x
& 0xF0000000U
)) {
1340 if (!(x
& 0xC0000000U
)) {
1344 if (!(x
& 0x80000000U
)) {
1353 * Return the minimum order for which x <= (1UL << order).
1354 * Return -1 if x is 0.
1357 int utils_get_count_order_u32(uint32_t x
)
1363 return fls_u32(x
- 1);
1367 * Return the minimum order for which x <= (1UL << order).
1368 * Return -1 if x is 0.
1371 int utils_get_count_order_u64(uint64_t x
)
1377 return fls_u64(x
- 1);
1381 * Obtain the value of LTTNG_HOME environment variable, if exists.
1382 * Otherwise returns the value of HOME.
1385 char *utils_get_home_dir(void)
1390 val
= lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR
);
1394 val
= lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR
);
1399 /* Fallback on the password file entry. */
1400 pwd
= getpwuid(getuid());
1406 DBG3("Home directory is '%s'", val
);
1413 * Get user's home directory. Dynamically allocated, must be freed
1417 char *utils_get_user_home_dir(uid_t uid
)
1420 struct passwd
*result
;
1421 char *home_dir
= NULL
;
1426 buflen
= sysconf(_SC_GETPW_R_SIZE_MAX
);
1431 buf
= zmalloc(buflen
);
1436 ret
= getpwuid_r(uid
, &pwd
, buf
, buflen
, &result
);
1437 if (ret
|| !result
) {
1438 if (ret
== ERANGE
) {
1446 home_dir
= strdup(pwd
.pw_dir
);
1453 * With the given format, fill dst with the time of len maximum siz.
1455 * Return amount of bytes set in the buffer or else 0 on error.
1458 size_t utils_get_current_time_str(const char *format
, char *dst
, size_t len
)
1462 struct tm
*timeinfo
;
1467 /* Get date and time for session path */
1469 timeinfo
= localtime(&rawtime
);
1470 ret
= strftime(dst
, len
, format
, timeinfo
);
1472 ERR("Unable to strftime with format %s at dst %p of len %zu", format
,
1480 * Return the group ID matching name, else 0 if it cannot be found.
1483 gid_t
utils_get_group_id(const char *name
)
1487 grp
= getgrnam(name
);
1489 static volatile int warn_once
;
1492 WARN("No tracing group detected");
1501 * Return a newly allocated option string. This string is to be used as the
1502 * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
1503 * of elements in the long_options array. Returns NULL if the string's
1507 char *utils_generate_optstring(const struct option
*long_options
,
1511 size_t string_len
= opt_count
, str_pos
= 0;
1515 * Compute the necessary string length. One letter per option, two when an
1516 * argument is necessary, and a trailing NULL.
1518 for (i
= 0; i
< opt_count
; i
++) {
1519 string_len
+= long_options
[i
].has_arg
? 1 : 0;
1522 optstring
= zmalloc(string_len
);
1527 for (i
= 0; i
< opt_count
; i
++) {
1528 if (!long_options
[i
].name
) {
1529 /* Got to the trailing NULL element */
1533 if (long_options
[i
].val
!= '\0') {
1534 optstring
[str_pos
++] = (char) long_options
[i
].val
;
1535 if (long_options
[i
].has_arg
) {
1536 optstring
[str_pos
++] = ':';
1546 * Try to remove a hierarchy of empty directories, recursively. Don't unlink
1547 * any file. Try to rmdir any empty directory within the hierarchy.
1550 int utils_recursive_rmdir(const char *path
)
1554 int dir_fd
, ret
= 0, closeret
, is_empty
= 1;
1555 struct dirent
*entry
;
1557 /* Open directory */
1558 dir
= opendir(path
);
1560 PERROR("Cannot open '%s' path", path
);
1563 dir_fd
= lttng_dirfd(dir
);
1565 PERROR("lttng_dirfd");
1569 path_len
= strlen(path
);
1570 while ((entry
= readdir(dir
))) {
1573 char filename
[PATH_MAX
];
1575 if (!strcmp(entry
->d_name
, ".")
1576 || !strcmp(entry
->d_name
, "..")) {
1580 name_len
= strlen(entry
->d_name
);
1581 if (path_len
+ name_len
+ 2 > sizeof(filename
)) {
1582 ERR("Failed to remove file: path name too long (%s/%s)",
1583 path
, entry
->d_name
);
1586 if (snprintf(filename
, sizeof(filename
), "%s/%s",
1587 path
, entry
->d_name
) < 0) {
1588 ERR("Failed to format path.");
1592 if (stat(filename
, &st
)) {
1597 if (S_ISDIR(st
.st_mode
)) {
1598 char subpath
[PATH_MAX
];
1600 strncpy(subpath
, path
, PATH_MAX
);
1601 subpath
[PATH_MAX
- 1] = '\0';
1602 strncat(subpath
, "/",
1603 PATH_MAX
- strlen(subpath
) - 1);
1604 strncat(subpath
, entry
->d_name
,
1605 PATH_MAX
- strlen(subpath
) - 1);
1606 if (utils_recursive_rmdir(subpath
)) {
1609 } else if (S_ISREG(st
.st_mode
)) {
1617 closeret
= closedir(dir
);
1622 DBG3("Attempting rmdir %s", path
);
1629 int utils_truncate_stream_file(int fd
, off_t length
)
1634 ret
= ftruncate(fd
, length
);
1636 PERROR("ftruncate");
1639 lseek_ret
= lseek(fd
, length
, SEEK_SET
);
1640 if (lseek_ret
< 0) {
1649 static const char *get_man_bin_path(void)
1651 char *env_man_path
= lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV
);
1654 return env_man_path
;
1657 return DEFAULT_MAN_BIN_PATH
;
1661 int utils_show_help(int section
, const char *page_name
,
1662 const char *help_msg
)
1664 char section_string
[8];
1665 const char *man_bin_path
= get_man_bin_path();
1669 printf("%s", help_msg
);
1673 /* Section integer -> section string */
1674 ret
= sprintf(section_string
, "%d", section
);
1675 assert(ret
> 0 && ret
< 8);
1678 * Execute man pager.
1680 * We provide -M to man here because LTTng-tools can
1681 * be installed outside /usr, in which case its man pages are
1682 * not located in the default /usr/share/man directory.
1684 ret
= execlp(man_bin_path
, "man", "-M", MANPATH
,
1685 section_string
, page_name
, NULL
);
1692 int read_proc_meminfo_field(const char *field
, size_t *value
)
1696 char name
[PROC_MEMINFO_FIELD_MAX_NAME_LEN
] = {};
1698 proc_meminfo
= fopen(PROC_MEMINFO_PATH
, "r");
1699 if (!proc_meminfo
) {
1700 PERROR("Failed to fopen() " PROC_MEMINFO_PATH
);
1706 * Read the contents of /proc/meminfo line by line to find the right
1709 while (!feof(proc_meminfo
)) {
1710 unsigned long value_kb
;
1712 ret
= fscanf(proc_meminfo
,
1713 "%" MAX_NAME_LEN_SCANF_IS_A_BROKEN_API
"s %lu kB\n",
1717 * fscanf() returning EOF can indicate EOF or an error.
1719 if (ferror(proc_meminfo
)) {
1720 PERROR("Failed to parse " PROC_MEMINFO_PATH
);
1725 if (ret
== 2 && strcmp(name
, field
) == 0) {
1727 * This number is displayed in kilo-bytes. Return the
1730 *value
= ((size_t) value_kb
) * 1024;
1735 /* Reached the end of the file without finding the right field. */
1739 fclose(proc_meminfo
);
1745 * Returns an estimate of the number of bytes of memory available based on the
1746 * the information in `/proc/meminfo`. The number returned by this function is
1750 int utils_get_memory_available(size_t *value
)
1752 return read_proc_meminfo_field(PROC_MEMINFO_MEMAVAILABLE_LINE
, value
);
1756 * Returns the total size of the memory on the system in bytes based on the
1757 * the information in `/proc/meminfo`.
1760 int utils_get_memory_total(size_t *value
)
1762 return read_proc_meminfo_field(PROC_MEMINFO_MEMTOTAL_LINE
, value
);